!!! Multiple package instances within a single package slot have been pulled
!!! into the dependency graph, resulting in a slot conflict:

virtual/ffmpeg:0

(virtual/ffmpeg-0.10.3::gentoo, installed) pulled in by
=virtual/ffmpeg-0.10.3 required by (net-misc/minidlna-1.0.25-r1::gentoo, installed)
(and 3 more with the same problem)

(virtual/ffmpeg-9::gentoo, ebuild scheduled for merge) pulled in by
>=virtual/ffmpeg-9[encode] required by (media-tv/xbmc-9999::x-portage, ebuild scheduled for merge)

It may be possible to solve this problem by using package.mask to
prevent one of those packages from being selected. However, it is also
possible that conflicting dependencies exist such that they are
impossible to satisfy simultaneously. If such a conflict exists in
the dependencies of two different packages, then those packages can
not be installed simultaneously. You may want to try a larger value of
the --backtrack option, such as --backtrack=30, in order to see if
that will solve this conflict automatically.

For more information, see MASKED PACKAGES section in the emerge man
page or refer to the Gentoo Handbook.

The following keyword changes are necessary to proceed:
(see "package.accept_keywords" in the portage(5) man page for more details)
# required by virtual/ffmpeg-9
# required by media-tv/xbmc-9999::x-portage[vdpau]
# required by xbmc (argument)
=media-video/libav-9999 **

Use --autounmask-write to write changes to config files (honoring
CONFIG_PROTECT). Carefully examine the list of proposed changes,
paying special attention to mask or keyword changes that may expose
experimental or unstable packages.

Does XBMC-9999 really require ffmpeg-9? Looks like it masked as well as other stuff already requiring ffmpeg-10. Also adding the "=media-video/libav-9999 **" changes nothing.

Does XBMC-9999 really require ffmpeg-9? Looks like it masked as well as other stuff already requiring ffmpeg-10. Also adding the "=media-video/libav-9999 **" changes nothing.

Saundersx ... it requires both virtual/ffmpeg-9 and media-video/ffmpeg-1.2.1 both of which are currently masked. I assume that this is a case in which libav isn't supported as an option as virtual/ffmpeg-9 could be provided by either >=media-video/libav-9 or >=media-video/ffmpeg-1.1. So it looks like your options are limited as the only way forward is to replace libav with ffmpeg (but you may have some issues with net-misc/minidlna) to do this you will need to unmask both the virtual and ffmpeg:

/etc/portage/package.unmask

Code:

=virtual/ffmpeg-9
media-video/ffmpeg

/etc/portage/package.accept_keywords

Code:

=media-video/ffmpeg-1.2.1
=virtual/ffmpeg-9

I'm currently using ffmpeg-1.2.1 without issues, the mask seems to be mostly in place as not all packages will build/work with it.